This invention relates to electrolytic cells, and particularly to electrolytic cells having a separator and a gas electrode.
Most electrolytic cells have two electrodes spaced apart by a separator. The separator is a member designed to impede the flow of liquids between the two electrodes. Separators are often composed of a mat of fibrous material or an ion exchange membrane sheet supported by a screen-like support member. It is important that the separator be held firmly in place to minimize excessive flexing, which causes cracks or breaks in the separator and defeats its purpose. Corrosion problems make it difficult to supply a support member that will provide the necessary rigidity over a long period of time.
To provide the necessary rigidity, it would be desirable to support the separator on an electrode. However, it is impossible to support separators on some recently-developed gas electrodes of the type described in U.S. Pat. Nos. 4,179,350; 4,187,350; 4,197,367; 4,213,833; 4,256,545; 4,260,469; and 4,269,691.
These gas electrodes have a plurality of passageways traversing the electrode which provide a pathway for liquids and gases to enter and exit the electrode. In the operation of these electrodes, a gas-liquid interface is formed by flowing a gas reactant into the passageways from one face of the electrode and flowing a liquid reactant into the passageways from another face of the electrode. Electrochemical reactions are caused to occur at this interface to produce a nonvolatile product.
If the separator were supported on a face of this type electrode, there would be no suitable exit from the electrode for the nonvolatile product. The only possible exits would be:
(1) through the gas side of the electrode; which would prevent additional gas from entering and cause the electrochemical reactions to cease; or
(2) through the separator and back into the adjoining electrode chamber where the product might be reconverted into reactants.
It would be desirable to rigidly support a separator on this type of gas electrode to minimize flexing while simultaneously providing a pathway for the removal of nonvolatile products.